@goldenshoe I didn't approach my GP first, no.
To be honest I have a real avoidance of going to the doctors anyway and have had a few poor experiences in the past of being "fobbed off" for various things - including something which lead to an extended stay in ICU and almost cost me my life.
So after reading around and realising that ADHD is commonly under-diagnosed in women (because people still see the young boy with ants in their pants stereotype) OR put down to other things such as depression and anxiety, I decided to just pay the money and bypass it all entirely.
With being in Scotland I couldn't have done Right To Choose anyway (which is where you go to your GP and ask to be referred to Psychiatry UK, making diagnosis and treatment free) so there wouldn't have been much point going to the GP since I'd have to wait two years at best even if they were supportive.
But if finances are tight (and you're in England) you might want to consider that route (GP then Right To Choose)? If so, I really recommend printing off the diagnostic criteria and going armed with a list of how it actually affects you in day-to-day life, with examples. My biggest fear was I'd get the "well everyone is a little forgetful sometimes, everyone procrastinates sometimes, everyones mind feels like it's running at 1000mph sometimes, everyone is a little impulsive."
So I was armed with a list of "yes, but does everyone else drive to B&Q at 9pm on a Friday night, spend £300 they don't have on decorating supplies, then not sleep for two days because they saw an ad for wallpaper on facebook?" "Does everyone else have a fridge full of food that went off two months ago?" "Does everyone else leave the house 10 minutes before an appointment that they KNOW is exactly 10 minutes away on an exceptionally good low traffic day, because of course it'll be alright?" "Does everyone else drink three cups of coffee before bed because caffeine has the opposite effect on them, and actually calms them down enough to sleep?"
That kind of thing. It really helps to have all the ways it's affecting your life written down and clear. I mean, like PPs on this thread I'm an intelligent person who did well at school and managed to have a good career. On paper, I'm doing just fine! But my impulsivity especially has ruined relationships and led to choices that have seriously impacted my life. It's important to get all those impacts clear, because imposter syndrome is a huge part of it and there's not a month that goes by where I don't question at least once if I'm really just a lazy idiot who fails at adulting and motherhood.
So all that said, if you have the money I recommend going private. It's nice not to have to "fight" and for the doctor to instantly affirm everything that you're saying is not actually normal, and not something that "happens to everyone sometimes".